Some recent non-dino papers:
Burrow casts with well-preserved, scratch traces form a complex burrow network.
The most likely tracemakers of these Karoo burrows are non-mammalian cynodonts.
Burrowing occurred in crevasse splays adjacent to laterally migrating river channels.
The 3D burrow network is comparable to pre-Jurassic tetrapod burrows globally.
The Middle Triassic is key in the evolution of complex vertebrate burrowing.
Abstract
Containing one of the richest late Early to early Middle Triassic continental biotas globally, the Burgersdorp Formation of the main Karoo Basin in South Africa hosts a diverse vertebrate fossil assemblage. Comparatively, trace fossils in this unit are lesser known, and thus how the Burgersdorp biotas behaved and interacted with their palaeoenvironment remain enigmatic. Here we report on two Middle Triassic continental ichnofossil localities dominated by tetrapod scratch traces from the Anisian part (subzones B and C) of the Burgersdorp Formation in the main Karoo Basin (Eastern Cape, South Africa). Analyses of the trace fossils and associated sedimentary facies aim to identify the possible trace makers, their behaviours and the local depositional conditions in this southern part of Pangea. We establish the palaeoenvironmental context for the ichnofossils combining ichnological data with the sedimentological records of the trace fossil sites and the nearby type area of the Burgersdorp Formation. To facilitate comparisons with similar trace fossils in the future, we quantify the morphometric parameters of these Burgersdorp trace fossils in digital models. Our results show that bilobated, branching and cross-cutting furrow casts with abundant scratch traces: (a) were generated within crevasse splay deposits adjacent to laterally migrating river channels in a semi-arid setting, and (b) can be interpreted as the claw-scratched ventral walls of a therapsid burrow system with a 3D network architecture. This well-developed vertebrate burrow network complex from the Middle Triassic of South Africa is among a handful of similarly complex vertebrate trace fossils in the global pre-Jurassic ichnological record. Collectively, these trace fossils indicate that the Triassic, and in particular the Middle Triassic, was an important period in the evolutionary history of the complex vertebrate burrowing.
======
Glyptosaurine lizards (Glyptosaurinae, Anguidae) are an extinct group of heavily armored lizards known from North America, Europe and Asia. Glyptosaurine lizards, taxa that possess fully developed tuberculated dermal armor, appear to have been established in North America by late early Puercan time (To3). "Proxestops," a taxon distinguished by a combination of vermiculate and tuberculated osteoderm sculpturing, is considered to be a non-glyptosaurine, a sister taxon of the Glyptosaurinae. Known from only fragmentary remains, its wide chronostratigraphic distribution suggests that "Proxestops" is a form genus that, in all probability, represents more than one taxon, that ranges from the middle Paleocene to the early Eocene of North America. Moreover, the taxa Odaxosaurus piger, Parodaxosaurus sanjuanensis and "Proxestops" are best considered "proto-glyptosaurines". "Melanosaurins" and glyptosaurins were well-established by the early Eocene, especially in North America, and are here documented by their type species and chronostratigraphic levels. Both tribes are present in Europe (MP7), too, but the record is not as estensive as that of North America. The North American taxon Gaultia silvaticus (Wa0) is transitional between a "melanosaurin" and glyptosaurin. Because it lacks the well-defined hexagonal osteoderms that characterize the Glyptosaurini, it is removed from that group and considered to be a "melanosaurin". The "melanosaurin" taxon "Xestops" savagei (Wa4âWa6) cannot be referred to Xestops (Br2) based on non-corresponding elements and because superficial similarity does not justify assignment to this taxon. Arpadosaurus sepulchralis (Wa6?), whose holotype is a fragmentary right frontal, is considered a subjective junior synonym of A. gazinorum, based on minor differences in the epidermal scale pattern that probably represent individual variation. "Glyptosaurus" agmodon (Wa6?), based on a partial right maxilla, cannot be referred to Glyptosaurus (sensu stricto), and the material upon which this taxon is based bears strong resemblance to material identified as cf. "?Paraglyptosaurus" yatkolai (Wa5âWa6). "Glyptosaurus" rhodinos (Wa5) is based on an incomplete parietal, and its reference to Glyptosaurus is considered problematic. Eoglyptosaurus donohoei (Wa7) is probably valid and is re-established here. Glyptosaurus (sensu stricto) is known solely from the middle Eocene (Br2) by G. sylvestris. Dimetoposaurus wyomingensis (Br3) is removed from Xestops vagans because its synonymy was based on superficial similarities. Helodermoides tuberculatus, the largest and last glyptosaurin (Ch3), is restricted to the Chadronian of North America. Only the "melanosaurin" Peltosaurus granulosus (Or2âOr3), which includes the species P. abbotti, seems to have crossed the Eocene-Oligocene boundary, and appears to be largely restricted to the Orellan, but extended into the Arikareean. European glyptosaurines are also represented by both glyptosaurins and "melanosaurins" early in the Eocene (MP7). Placosauriops-like "melanosaurins" are known from Dormaal (MP7), and the glyptosaurin taxon?Placosaurus ragei occurs at the same level. "Placosauriops abderhaldeni" has been identified from the Grube Messel (MP11), but this assignment remains dubious because the species has not been adequately diagnosed, and the holotype species is from the Geiseltal (MP13), which is some 4.5 million years younger. Placosauriops weigelti (MP13) is the only valid species of this genus. Paraxestops stehlini (MP14) is not referable to the North American taxon Xestops, and its relationship to Placosauriops has not been studied. The late Eocene glyptosaurins Placosaurus estesi (MP17) and P. rugosus (MP18) are the last glyptosaurines known from Europe and appear to have gone extinct at the Eocene-Oligocene boundary, casulties perhaps of the "Grande Coupure". Asian glyptosaurines are known solely from one species, Stenoplacosaurus mongoliensis, from the middle Eocene (Sharamurunian) of China. Glyptosaurines most likely originated in North America, diversified by late Paleocene time, and rapidly spread across the North Atlantic into Europe by the early Eocene. Both "melanosaurins" and glyptosaurins took a foothold in Europe by the early Neustrian, but the glyptosaurins, aside from one occurrence (Dormaal, MP7), were conspicuously absent for most of Neustrian through early Robiacian time. In North America, glyptosaurins diversified during the early and middle Eocene, while in Europe small "melanosaurins" were a prominent part of the paleoherpetofauna, and glyptosaurins are unknown for most of the Neustrian through the Geiseltalian, in both the fossilferous LagerstÃtten of Messel and Geiseltal. Stenoplacosaurus is the only known glyptosaurin glyptosaurine from Asia, and its abrupt appearance during the late Eocene suggests the possiblity of a Beringian dispersal from North America into Asia.
===
Free pdf:
Strisores is a clade of neoavian birds that include diurnal aerial specialists such as swifts and hummingbirds, as well as several predominantly nocturnal lineages such as nightjars and potoos. Despite the use of genome-scale molecular datasets, the phylogenetic interrelationships among major strisorean groups remain controversial. Given the availability of next-generation sequence data for Strisores and the cladeâs rich fossil record, we reassessed the phylogeny of Strisores by incorporating a large-scale sequence dataset with anatomical data from living and fossil strisoreans within a Bayesian total-evidence framework. Combined analyses of molecular and morphological data resulted in a phylogenetic topology for Strisores that is congruent with the findings of two recent molecular phylogenomic studies, supporting nightjars (Caprimulgidae) as the extant sister group of the remainder of Strisores. This total-evidence framework allowed us to identify morphological synapomorphies for strisorean clades previously recovered using molecular-only datasets. However, a combined analysis of molecular and morphological data highlighted strong signal conflict between sequence and anatomical data in Strisores. Furthermore, simultaneous analysis of molecular and morphological data recovered differing placements for some fossil taxa compared with analyses of morphological data under a molecular scaffold, highlighting the importance of analytical decisions when conducting morphological phylogenetic analyses of taxa with molecular phylogenetic data. We suggest that multiple strisorean lineages have experienced convergent evolution across the skeleton, obfuscating the phylogenetic position of certain fossils, and that many distinctive specializations of strisorean subclades were acquired early in their evolutionary history. Despite this apparent complexity in the evolutionary history of Strisores, our results provide fossil support for aerial foraging as the ancestral ecological strategy of Strisores, as implied by recent phylogenetic topologies derived from molecular data.Â
===
Christian PÃntener, JÃrÃmy Anquetin & Jean-Paul Billon-Bruyat (2019)
New material of "Eurysternidae" (Thalassochelydia, Pan-Cryptodira) from the Kimmeridgian of the Swiss Jura Mountains.
PaleoRxiv (preprint)
DOI: 10.31233/
osf.io/4g3pqhttps://paleorxiv.org/4g3pq/The region of Porrentruy (Swiss Jura Mountains) is known for its rich and diverse assemblage of Late Jurassic coastal marine turtles (Thalassochelydia). Dominated by the âPlesiochelyidaeâ, this assemblage also includes representatives of the two other thalassochelydian groups, the âThalassemydidaeâ and âEurysternidae.â In this study, we present new shell-based material from Porrentruy referable to eurysternids. One specimen represents a juvenile individual or a relatively small taxon, and is notably characterized by a well fenestrated plastron exhibiting a wider than long central plastral fontanelle. Two other specimens are much larger and possibly represent the largest eurysternids known to date. The fourth specimen is characterized by a unique plastral morphology otherwise only known in very small juveniles. This is the first time this unique plastral morphology is known to persist in an adult or subadult. The new material described herein represents at least three distinct taxa, all of them probably new. However, we refrain from naming new species based on this incomplete material in order to avoid adding confusion to an already complex taxonomical situation. This study provides new insights into the great diversity of eurysternids during the Late Jurassic.